Christians are confused, insulted, and even infuriated that skeptics do not accept the list of eyewitnesses to the bodily resurrection of Jesus, as listed in the Early Creed quoted by Paul in First Corinthians chapter 15, as historically reliable. “Do skeptics think that the early Christians would make this list up? The early Christians were risking their lives by preaching this stuff! That makes no sense!”
Most skeptics accept the early dating of the Creed, and, most skeptics do not believe that early Christians just made up this list of eyewitnesses. Most skeptics believe that early Christians sincerely believed that they had seen the resurrected Jesus. However, we skeptics believe that the most probable explanation for this belief is not a miraculous, once in history resurrection, but some natural phenomenon, or collection of phenomena, which the early Christians innocently confused for a miracle.
Some Christians demand that we skeptics give evidence for any alternative explanation for the early Christian resurrection belief, but we skeptics are under no obligation to prove an extra-ordinary claim to be false nor are we under any obligation to provide evidence for any one naturalistic explanation. The onus is on Christians to provide the evidence for their extra-ordinary claim, and, to demonstrate that all possible naturalistic explanations are impossible. If even one naturalistic cause is possible to explain the event, and it can be shown that this naturalistic cause has happened more than just once in human history, then by simple mathematics, a naturalistic explanation is more probable than a once in history miracle resurrection.
So what possibly gave rise to the early Christian belief in the post-death appearances of a resurrected Jesus? Here is one possible scenario:
The chief disciple, Peter, has a vivid dream, or a trance, in which Jesus appears to him and tells him that he has been resurrected by the power of God and shows him his wounds as proof. The next day, Peter announces to the disciples that Jesus has been resurrected and that Jesus has appeared to him! The disciples who had been in deep despair since the sudden death of their leader are jolted with excitement bordering on hysteria. Soon several other disciples receive similar appearances by Jesus in dreams or trances. And shortly thereafter as the Twelve (including Matthias) are sitting on a hillside, a bright light appears at the top of the hill. It is so bright it is blinding. It takes the shape of a cross then it disappears!
“It was Jesus! He has just appeared to the Twelve!”
A few weeks later, a similar phenomenon happens to a group of five hundred believers!
And it is these events upon with the Early Creed is based, and from which, many decades later, embellished stories of groups of women coming to an empty tomb, multiple earthquakes, multiple celestial beings, and multiple dead saints roaming the streets of a major city, emerge to give us the Gospels.